This project is designed to determine how 2 designated control gene 1oci (I and B1) of the fowl effect their changes during melanogenesis with regard to the structural c and pk loci. During the year 1/1/76-12/31/76 we propose to investigate how the wild type inactivated pigment cell genes in chick embryo erythrocytes restore normal pigment synthesis in mutant c and pk melanocytes after somatic cell fusion. Complementation studies using pk erythrocytes and c melanocytes will also be undertaken. Meanwhile genetic stocks involving combinations of 4 mutants will be produced so that control gene function can be tested in the future using a battery of fusion tests. Methodology involving cloning, selection, karyotyping, and "mini- cell" (by product of enucleation) production using these primary cultured neural crest derived melanocytes will also be developed. Bibliographic references: Carver, V. and Brumbaugh, J. 1974. Melanocyte developmental genetics; Biphasic control of dopa oxidase activity by the E locus of the fowl. J. Exp. Zool. 190:353-366.